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OS_Claim
Programmer's Reference Manuals
» Part 15 – SWI Calls
» OS
» OS_Claim
OS_Claim
(SWI &1F)
| Entry | |
|---|---|
| R0 | Vector number |
| R1 | Pointer to address of claiming routine |
| R2 | Value to be passed in R12 when the routine is called |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Preserved |
| R2 | Preserved |
Use
The purpose of this call is to add a routine to the list of those that claim a vector.
Notes
This call adds the routine whose address is given in R1 to the list of routines claiming the vector. This becomes the first routine to be used when the vector is called.
Any earlier instances of the same routine are removed. Routines are defined to be the same if the values passed in R0, R1 and R2 are identical. If you wish to add multiple ‘identical’ routines use OS_AddToVector.
The R2 value enables the routine to have a workspace pointer set up in R12 when it is called. If the routine using the vector is in a module (as will often be the case), this pointer will usually be the same as its module workspace pointer.